Node editor, pick random Image Texture from set?
This Randomizer Node Setup should work for what you want to make. If you want you could also switch up the mix shaders for mix color nodes to only randomize the images but I would suggest randomizing the shaders because 1. you only have to do this setup once and 2. you can individually control for example the strength of the bump map and the mixing factor of glossy and diffuse and so on...

Just to explain whats going on here: I have that Random number from the Object Info Node and multiply it with 4 to have a Number between 0 and 4. Then I split that range in half by checking of it is greater or less than 2. Then repeating the same procedure splitting that ranges in half but checking greater 1 and greater 3 if that makes sense.